#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>

int main()
{
	char buf[100] = {};
	
	printf("please input:\n");
	int res = read(0,buf,99); //标准输入---键盘 
	printf("%d,%s\n",res,buf);
	write(1,"hello\n",6);//标准输出---屏幕
	write(2,"welcome\n",7);//错误输出---屏幕 
}